Electrolytic apparatus for treatment of moving strip



ELECTROLYTIC APPARATUS FOR A 2, 1949- c. G. JONES 2,477,808

Filed May 8, 1946 3 Sheets-Sheet 1 TREATMENT OF MOVING STRIP INVENTOR 4/?1. 6.. Jami:

ATTORNEY Aug. 2, I949.

C. G. JONES ELECTROLYTIC APPARATUS FOR TREATMENT OF MOVING STRIP s Sheets-Sheet 2 Filed May 8. 1946 ATTO R N EY INVENTOR 64AM G Jim/E5 BYZ Aug. 12, 1949.

c s. JONES 2.477.808 ELECTROLYTIC APPARATUS FOR -5.REATMENT 0F MOVING STRIP Fild May s, 1946 I/II III/II l l J INVENI'OR 54/74 6: James ATTORNEY Fig.5.

Patented Aug. 2, i949 '1 'ELEoTRoLYTIo APPARATUS iron TREAT MENT 0F MoyI Gjs'riuP Carl G. J ones, Youngstown; Ohio Application May s, 1946, seri'elio. 668,183

; invention relates to electrolytic processing oi'm'e'ta'l stripan'd is especially directed to'impr, ements in electrolytic apparatus whereby be 'ntienyincreasedfjprquucnon of electrolytic ate .iiie' :befgattejinegiy with maximum unifoimity. of". eating thickness, as compared with electrolytic. tin plate "heretofore commercially manufactured."

4 ,lijsheenproposedian electrolytic coating latinglfrnachiriefoi'. steel,strip comprising a drum suspended in a tank, a no'des proximate the outer suit'iace jof thejdfrurn, either of tin'and therefore soluble,.inthe Hath'toreplace the metal deposited on the strip or els'e'relatively insoluble, and means for supplying, electrolyte to the tank as Qthe strip acting "as thecathode is continuously moved 'overthejdrum between it and'the anodes.

Buemep emjms of this general character it has been "found difficult; if not" impossible, to

produce a high-yield'of -tin plated's'teel-strip with satisfactorily uniformthick'nes's of tin coating across its width as the plating current tends to concentrateadjacentthe edges of-the strip andt-h'us-cause excessive deposition of tin in those areas a-scomparedwith the center portion of the strip;'while' non-uniform flow of electrolyte in contact with-th'e strip tends-to impair I the quality of coating when relatively high-rate production is attempted-"due to spent solution not being flushed away from' the strip surface with =uniform or-su ilicient rapidity after the tin i ions have been deposited therefrom: on :the strip.

' M'cr-eoyer; 'the diflicultiesincident to 'threading; striptthrough theiapparatusat thel initiation oflits'operation and of -passingithrouch tit :defeotime welds',- .which unavoidablycoccur iinusecuring: togetherxtliecends ofpsuccessive' strips stoxforrrr;a continuousmne, have served asifurthendeterrents Another object is to pr -v'ole apparatus of this -5 Claims. (01. 204-211) 7 e ec r yte- 2 character in which a plurality of relatively'ad justahle electrodes supply current for the ele 7 trolytic treatment and also serveas condu the passage of freshelectrolyte intothe loath'and into intimate contactwith the strip race;

A further object is to provide apparatus'iir which such adjustable electrodes, Iarrarigd T substantially parallel planes spaced .transxiers of the path of the strip, may .be selectively rend'ered ineffective in the, electrolytic treatment, whereby strips offdifi'erent' widths .rnay readily be successively accommodated'ior treatment al i likejuniformity in the latter attained sulo stanr tially irrespective" off difii ences instrip width. 15 V :A still "iurtherjobjectis to provide novel means for carrying current'to theadjustable electr des in such apparatus 'wherehy the current is e tributed al n the l n t of qh whil QQPQE?" tively positioned ,but when inflp v fativ e currentyv be wi hhel the e rom, wh re y a ough the electroderema-ins in the electrolytic loath it: a nqe cqte nithetr atm b inac iedout, its mov men to in perativ mosition.havine' nterrunted;itsfunctioning as a conduit for iresh =A s ti1l furtherobjectds to provide apparatus; which, .While perhaps primarily .mostns'eful for electrolyticallydepositing artin' coating onsteel strip; -in@the-manufacture of commercialtin plate,

may-also beiused :fordepositine other metals ori steel orothermetallicstrips-or may be usedion electrolytic. cleaning or i pickling of steel or other metal 'strips without change in its structure.

Other objects,-purposes and advantages of-the invention will lhere'in after more 'fully appear er be understood from the following description of a preferred embodiment of it as shown in the accompanying drawings and during which to facilitate the disclosure Iinay emphasize ast stronglyits use in tin plating steelstrip as illustrative of theseveral electrolytic'processes where-- in it may be advantageously employed.

I In the said drawingsiFig. l'isa somewhatdia' grarnniatic side 'elevationof the apparatus;

Fig.2 is an end view thereof;

Fig, 31 is an enlarged vertical "section on incline sac-111mg. 2; j

Fig. dis a fragmentary furtherenlarged detail of one anodeclampand-connector assem Figs. 5 and dare sectional viiews .on lines- 5 v5- and..6,.6 respectivelyin Fig. .4; f A

Fig. .7 ;is a V fragmentary. enlarged detail shpw ingl several anodes-andapart ofthe-cathode in horizontal section} Fig. 8 is a fragmentary enlarged detail of the electrolyte inlet pipe and associated parts; and

Fig. 9 is a fragmentary detail, partly in section, of other anode connectors.

In the several figures like characters are used to designate the same parts.

Referring now more particularly to the drawings, the apparatus generally illustrated in Figs. 1 and 2 comprises a tank T provided with an inlet pipe I through which electrolyte may be supplied by a pump (not shown) and an outlet pipe for removal of spent electrolyte from the tank, this pipe having a valve V for maintaining a suitable constant level L of the electrolyte therein by controlling the flow of spent electrolyte therefrom. Disposed above the tank on suitable supports (not shown) are guide rollers G over which a strip S passes in its travel into and from the tank.

Within the tank is a hollow open-end drum I0 comprisin an inner cylinder II, outer cylinder I2 and an intervening cylindrical layer of micarta or other suitable insulationit, the drum being supported on flanged rollers 'I 4, I5 carried in bearings I8, I 7 on the sides of the tank. The roller flanges I8 extend radially from the main body of the rollers a distance less than the combined radial thickness of inner cylinder II and insulation I3 and the drum as a whole is thus rotatable on its own axis while supported on the rollers in metalto-metal contact, but with its outer surface, that of cylinder I2, electrically insulated from the rollers. If desired the drum may be formed sectionally from a plurality of identical inner and outer rings insulated from each other and held together axially in any convenient way, but as the present invention is not concerned with the specific construction of the drum no further description of it is required.

'Above the drum and supported independently thereof, I provide a current collector I9 comprisingmeans engaging the drum surface for conveying the electrolyzing current between the drum and one pole of the current source (not shown) but the specific construction of the collector is also of no concern in the practice of this invention, it being adequate for the purposes thereof that a, rotatable drum be provided with means for electrically.lconnecting it with the current source, usually the negative pole of the latter.

.However, the electrodes of opposite polarity, usually the anodes, are of special and novel construction and in accordance with the invention a plurality of them are arranged in pairs respectively spaced axially of the drum at suitable intervals; as the anodes comprised in each pair are similar though arranged in opposite relation with respect to the drum, specific description of but one such pair is required. Thus each pair comprises a leading anode 28, extending generally arcuatey from near the bottom of tank T normal to the drum axis and toward the incoming strip and a trailing anode 2i extending correspondingly in the general direction of the outgoing strip. Each anode comprises a curved pipe or tube 22 shaped to conform generally to that part of the drum it overlies when in operation and is supported at one end from a ring or collar 23 embracing inlet pipe I, the collar having a hole extended through it in alignment with the passage in the anode, while the inlet pipe is provided with a port 24 for admission of electrolytic fluid from the pipe to each anode when in position to communicate therewith through registry of the hole in the collar. All these collars are movable on the pipe relatively to each other and are provided with gaskets 25 to prevent escape of electrolyte between them, and the flow of electrolyte from inlet pipe I into the tank thus requires at least some of the anodes be positioned to communicate with the pipe, the volume of flow of course being in proportion to the number thereof so communicating at any given time.

The anode tubes as noted are curved in general conformity with a sector of the drum, and each has welded to its inner face an anode bar 30 having rounded inner edges and a series of spaced ports 3i aligned with corresponding holes in the tube, whereby electrolyte introduced under pressure through the inlet pipe I passes through anode tube 22 and ports 3i and is projected forcibly against the adjacent surface of strip S when the anode tube is in communication through port 24 with the pipe. Alternate anode bars 30 are provided with arcuately formed hard rubber or other dielectric strip guides 32 conforming generally to but projecting radially inward a little beyond the inner faces of the anode bars, for a purpose which will hereinafter appear.

The upper end of each anode carries an anode extension in the form of a relatively fiat upstanding blade 35 projecting between a pair of terminal bars 36 and supporting a contact clamp assembly comprising a pair of rotatable clamping discs 31, 38 secured by set screws 39 to a stud 40 on which threaded collars 4| assist in holding the discs firmly on the stud but rotatable therewith relatively to the anode extension. The discs 31, 38 are oppositely arcuately and eccentrically beveled on their inner faces to form with blade 35 grooves receiving the upper correspondingly beveled edges of terminal bars 36, one of the discs being provided with a clamping rod 42 whereby the entire clamp assembly may be rotated to engage terminal bars 36 between the discs and the blade or to free the latter therefrom, the bars being curved on an are (exaggerated in Figs. 4 and 9) whose center is the center of inlet pipe I about which the entire anode, including its extension and clamp assembly, is movable as before described. Adjacent the base of, and between each pair of bars is a thin layer of insulation 44 within which the blade enters when fully retracted, and as in this position the clamp assembly is usually in released position, electrical connectionbetween the base and blade is thus interrupted, but is restored when the clamp is actuated, at any position of the anode, to engage the bars.

Additional connections between the terminal base 49, which supports bars 36, and each anode are provided by flexible cables 50, 5| respectively secured at points spaced along the curve of the anode to anode tube 22 and having severable electrical connection with the terminal base through plugs 52 provided with tapered heads 53 and extending through insulating sleeves 54 in holes 55 in the terminal base. Nuts 56 on the plugs enable the latter to be drawn up so their heads engage the adjacent tapered ends of holes 55 to effect electrical contact with the base, or when backed off, to interrupt electrical connection therewith.

Itwill thus be apparent that when the clamp assembly is operated to engage the bars, and especially to hold the corresponding anode in operatively adjusted position proximate the drum, and the nuts 56 are set up on plugs 52, electrical connections are established between the terminal base and the anode to distribute current along the anode at three spaced points, or at any other will steel" saw-rea cables 50, 5-l a assh'iated parts"proYiddY uSiIalIy twoare 'sufli- I cieiit andthisfniiliib'r therefor is preferred as suitable under 130st conditions of normal use of m thermos;- the' 0th connected. with collector- Td'en a'nb' understanding of thehat'ur'e of the apparatus erein Slfiblllf anddscribe'd; reference" ow bemade to itsi-use in electrolytic tin ing' 'o'ne side" bf] a 'steel stri'p s from which" it beevident-th onlfn de aria-tenant will e p ated subsque'nny msminar' apparatus-' and is -desirable fronr an economic standpoint that alkaline valu'es' be conserved; spent solution drawmfrom'the plann tank is preferablyreturnedtosu'chleaching plant for regeneration andireire'wal of its tin ion concentration.-

.Mor'eoven' thes'aid apparatus requires,- as has be n-npted,-a source of current, preferably a low 'vltaig dli'rect current-of; about 9 volts 'and amperagl"'adequateto provide-up t'o about750 to- 1000 an'i'p'eres, orev'en'rnore'; per square foot of s'trip surface being subjected to J'electroly tic de'posinon- 0ftin at any onetime. the strip is'usually v in continuous mom-n through the apparatus it willbe understoodthe area'u'sed in calculating; the current strength is but asmall-portion of the total area Of any Strip of'usual'lengthg-bemg a 5';

function practically solely of the strip" width, plating drumdiarnete'r and'plating drum submersion'in the electrolyte. v Depending on the strip width; either soi'ri or all the anodes win actuallycontribute to the results attained; thoS ndt fedllir ed, silchlas those 5 at'the' opposite ends of the groups on either side o'f'the druin 'whena'n'arrow strip-is being plated, being nierely lIiOV 'Qd'tO inoperative position 'orre spondin'g' gerierallyto' that 'of "anode 2 l at the'left' inFi'g. 3, Withit's"cable connections interrupted; while theanoas ne rer the ("enter or each group are positioned oprativeiy nearer'the drum surfae'and the strip as in the os tion of anode 20 I in said figure. Whenthe :s'tripis initially threaded throu'gh'the apparatuain end is passed first over one guide roll, then partially around the drum and oyer th'e secondgiiide rollwhile all the anodes are retracted t0 inoperative position, as they are then: spend their aximum di'stancefront-me druin; which facilitates the threading operation; The'leading end is or course then passed to wind iriinec'hanisni"(not shownr or other apparatus, sues-a a secondjsirnilar tank Where its other sidefrr iaybe plated, but in any case'a substantial j 'f' faintained orythestrip and its linear r'a e1 through the platih apparatus, subject to control by operator,"maintaine'd at a speed" su te-pie eriti e bbhd lp ns of temperature; l'tiolyfi "81561 121311; 'llir'el'it density and other the ame wan-and that=thetin plating of e; of; a" source of electrolyzing tie with the termihal base 49'? l the invention is notdi'rectly' concernedh11t i factors attainment? pr diiEiin g' bii tir strip" coating o'f'the desirerlthiekne The electrblyte niay b ke -fairlt hotz sliclnas" at 1 abate-190 F; w en aiming solutions ar used for"tifi-platin heat bein gsupplie'd eithe by mtnsduem he tloiitlirough the'i'nletp I or by pos't'lonlhg' stearh hatihgtnafis e like in or near the tanl f j- 'The'enetrmytest ngth of coarseie eatenmned -=by= radars: with whit order totem-m me its rapi depletion'it is desirable; 1 a rainy sllbs'tafifiial llafl bl essiil beapplies]; tif th'e S'lifea'Jn' Of Sdliltioh' fit erirlg through 'lilelt lJiii I, asthe"'solution is" then ejcted forc'ibly fr dm the anodes again thestrip surface injets i threaten the--- anodeelectrolyte ports 31 and? rapidlystfieeps away the partially spent solutio be'folit'loses S0 mllhbf itstiir-idni-conten to' the strip asmaterially to re uce theratetiri depolsitiofifrorh if." surnameadjustment valve V- with relation to the incoming stream o electrolyte" maintains a substantially constant liquid level in the ta provided other "conditions I remain substantially 'stati'c, and as they cha ge the valve may require adjustment from "time 't'd tirrie; since any materlal'rising of the n mdi-evd during-plating reduces the current density T and" consequently may impair the uniformity or thick-' ness of the finishedcdating while a marked fall in the level, other things being equal; m ig ht' result-in increasing the current densitvabove; a": safeordesirable valliei 1 The current density at th strip suriac'e -isalso i subject *t'o control and-modification; independ erltly l of 1 the" current supplied from the source, the adjustment of anodes relatively to"the strip, a and as the positions-of the right le'ft hand 'anodeszfl and 2| in Fig.3 represent respectively substantiallythei lihiit-positions of" adjust ments) it will b eviden-t' that" when n anode is positioned like anode Z'O-insaid figure its barflfi closely conforms to" thelcurvlatur'e of thestrip en the adjacent drum surface and affords -a 'r'nini I mum length of current-travel through theelectrolyte 'be'tw'e'en- 'the anode and the strip; resulting in maximumusefurc'urrent'flow; lam-mallet; however, vthe anodes. adjacent the t edges of the strip are backedvoff a'small distance "from'=th'is"- position to counteract the tendency of the icurrent to concentrate atthe strip edges and inthisi- Way substantially-uniformcurrent density across the strip maintained, all .itcurren't carrying-1: anodes of course being clampedito the terminal bars by; their respectiveplamps 'andya1so; cone. m t to he te m a ha s: t rou het in up; 2th? ts an er resp ctiv c orll e w rnovement oi the strip in the direction of the arrow in Fig. 3 in engagement with-theflr um'rrotatesthe latter onits roller supports, and ;collector J9, y be sectionalijzed, especiallyasection alized drum is used-affords-adequate electrical contact with the drum for passage.pr urientbetweent e strip and the current source,"mus compieting the electroly zing.

7 ly'z ifngcurrnt is suppliedand an adequate now of '4 electrolyte'i'smaintained? I Further' re while reference has'th'ug been:v

made prihcipallyfto a sing e fstrijplit will be untended necessarily "asi'n e ingota'ndthereof the metal of one original piece, as'a'plurality of strips welded endto end are desirably fed successively and continuosly to the apparatus for plating. Such welds usually produce zones of increased thicknessin the strip as a whole, especially when the parts are carelessly lapped in welding, but such splices and other slight irregularities that may occur in the strip do not normally, affect the operation or effectiveness of the apparatus,.insulating guides 32 on alternate anodes being ordinarily effective to prevent any direct contact, between the strip and the anodes, such as might tend to short circuit the current source. There sometimes occur, however, conditions which result instrip splices or welds of abnormal thickness too great to pass between the anodes and the drum with safety when the former are in operative position, but as these are of rare occurrence and advance warning of their presentation'to the machine is normally given, itrequires but .a moment for an attendant, when or just before such splice reaches the apparatus, to loosen the anode clamps and retract the anodes, allowing the defective splice to pass through and beyond the apparatus without damage to either it or the strip and thereafter to reposition the anodes to allow the plating to proceed as before.

As I usually prefer to provide a minimum clearancebetween the strip face and the anode bars of about one-quarter inch, it will of course be apparent conditions requiringretraction of .the anodes as just described, with or without slowing or stopping of the strip as preferred, will ordinarily be of rare occurrence, but .are mentioned herein to emphasize the adaptability of my apparatus to abnormal conditions and to demonstrate the facility with which they may be met, and it is believed its operation under normal as well as' abnormal conditions for substantially any kind of electrolytic plating or other treatment of steel or other metal strips will be evident from the foregoing without further description.

It will be appreciated, however, that when the apparatus is used for cleaning or pickling the effects of combined electrolytic and mechanical action obtainable produce better results than either of these used singly or both successively in accordance with prior practices, as the mechanical impingement of the electrolyte projected in high velocity jets against the strip surface tends to break up any film of oil. grease, scale or the like on the strip while rapidly removing gases formed at its surface by the electrolytic action and also accelerates emulsification of oils and greases through mechanically mixing finely divided particles thereof with the electrolyte while current is flowing in the latter.

It'is of course to be understood that while I have herein described one embodiment of the invention with considerable particularity and suggested certain expedients which may be resorted to and alterations in conditions through modification of various adjustments and/or controls such as those of temperature, current, speed of strip travel, electrolytecomposition and flow and the like, I do not thereby desire or intend to limit or confine myself thereto or thereby in any way, or to the form, construction, arrangement or relationship of the several elements and/or parts comprised in the apparatus as these and numerous other changes and modifications such as will readily occur to those skilled in the art may be made if deemed advisable without departlngfrom the spirit and scopeof the invention as defined in the appended claims.

Having thus described my invention, I claim and desire to protect by Letters Patent of the United States:

1. In apparatus for progressively subjecting a strip to electrolytic action, a vessel for electrolyte solution, means for passing the strip therethrough along an arcuate path including a substantially toward the axis of said path, a collar surrounding said common axis supporting each electrode from one end thereof and providing a port communicating with said passage, a pipe extending through all the collars about which said collars are respectively rotatable, the pipe having ports respectively communicating with the collar ports when the corresponding collars are in positions to align their ports therewith, and means for supplying electrolyte under pressure to said pipe whereby said electrolyte is ejected from the apertures selectively in accordance with the positioning of the several curved electrodes and their supporting collars relatively to said pipe.

2. Apparatus for progressively subjecting a moving strip to electrolytic action comprising a drum supported for rotation about a fixed axis and constituting a contact element for the strip beneath the surface of a liquid electrolyte, a tank for holding the electrolyte, means for passing the strip partially about the periphery of the drum in contact therewith and with said electrolyte, a series of curved electrodes partially embracing the drum each having a plurality of spaced ports directed inwardly toward the axis of curvature of the .electrode and a passage communicating with the ports, the electrodes respectively conforming substantially to arcs of more than on radii greater than that of the drum and mounted for oscillatory movement in laterally spaced planes toward and away from the drum about a common axis parallel to the drum axis and lying adjacent and radially outwardly spaced from the path of the strip about the drum, and an inlet pipe coaxial with the paths of oscillatory movement of the electrodes having ports respectively positioned to communicate with the passage in an electrode when the latter is at the inner limit of its oscillatory movement to enable electrolyte to pass from the inlet pipe thereto, said communication being interrupted when the electrode is at the outer limit of said movement.

3. Apparatus for progressively subjecting a moving strip to electrolytic action comprising a drum supported for rotation about a fixed axis and constituting a contact element for the strip beneath the surface of a liquid electrolyte, a tank for holding the electrolyte, means for passing the strip partially about the periphery of the drum in contact therewith and with said electrolyte, a series of curved electrodes partially embracing the drum each having a plurality of spaced ports directed inwardly toward the axis of curvature of the electrode and a passage communicating with the ports, the electrodes respectively conforming substantially to arcs of more than 90 on radii greater than that of the drum and mounted for oscillatory movement in laterally spaced planes toward and away from the drum about a common axis parallel to the drum axis and lying adjacent and radially outwardly spaced from the path of the strip about the drum, supporting means for the electrodes having spaced ports respectively conforming to and positioned to register with the passages in the electrodes when each of the latter is disposed substantially at the inner limit of its oscillatory movement, communication between the supporting means and the electrodes through said ports being progressively restricted as the electrodes approach the outer limit of said movement.

4. In apparatus for progressively subjecting a strip to electrolytic action, a vessel for electrolyte solution, means for passing the strip therethrough along an arcuate path including a substantially cylindrical contact element supported for rotation about its axis adapted to engage the radial inner face of the strip while traversing said path, a series of axially spaced curved electrodes disposed radially outward from said path and conforming substantially thereto, and a ported tubular member having its axis parallel to that of said path but outwardly spaced from the path pivotally supporting an end of each electrode for oscillatory movement of the electrodes toward and away from the element about the axis of said tubular member, each port in the latter communicating through an electrode passage with a plurality of inwardly directed spaced apertures in the electrode for discharging electrolyte from the tubular member through the electrode passages and apertures radially inward toward said path.

5. Apparatus for progressively subjecting a moving strip to electrolytic action comprising a drum supported for rotation about a fixed axis and constituting a contact element for the strip beneath the surface of a liquid electrolyte, a tank for holding the electrolyte, means for passing the strip partially about the periphery of the drum a series of curved electrodes partially embracing the drum each having a plurality of spaced ports directed inwardly toward the axis of curvature of the electrode and a passage communicating with the ports, the electrodes respectively conforming substantially to arcs of more than 99 on radii greater than that of the drum and tubular supporting means for the electrodes positioned adjacent the drum and supporting the electrodes for oscillatory movement in laterally spaced planes toward and away from the drum about a common axis parallel to the drum axis and lying adjacent and radially outwardly spaced from the path of the strip about the drum, said tubular means having spaced outlets each conforming to and positioned to register with one end of the passage in a corresponding electrode for introducing electrolyte into the electrode passage for projection through the electrode ports toward said path when the electrode is at the inner limit of its permissive movement, communication through said outlet being progressively restricted as the electrode is moved toward the outer limit of its said movement.

CARL G. JONES.

REFERENCES CITED The following referenlces are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 895,163 Cowper-Coles Aug. 4, 1908 951,365 Cowper-Coles Mar. 8, 1910 1,412,909 Voigt Apr. 18, 1922 1,811,409 Thormann June 23, 1931 1,974,441 Andersen Sept. 25, 1934 2,271,735 Hall Feb. 3, 1942 FOREIGN PATENTS Number Country Date 419,391 Great Britain Nov. 12, 1934 547,312 Germany Mar. 31, 1932 

